Note: Descriptions are shown in the official language in which they were submitted.
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INTEGRAL CYLINDER LIFT MECHANISM
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BACKGROUND OF TEIE INV~NTIO~
1. Field of the Invention.
The pr~sent invention relates to a lift
mechanism for use with various agricultural and other
implements requiring height adjustment.
2. Description of the Prior Art.
In the prior art various lift cylinder
mechanisms have been advanced ~or raising large
implements, particularly tool bar frame implements
such as field cultivators and chisel plows. For
example, U.S. Patent 4/194,573 shows an ayricultural
subsoil implement having individual wheel assemblies
which are controlled by hydraulic cylinders ror
raising and lowering the support wheels relative to
the frame and -thus raising and lo~ering the frame
relative to the ground. The cylinders are directly
supported back to the frame, and ~his requires
substantial complexity in the design in order to
maintain the correct placement of the cylinder mount
location. ~urther, adjustments for adjusting the
cylinder position to compensate for wear is quite
difficult. This is particularly true where a stop
member is provided on the cylinder so that when the
cylinder is retracted it returns to a fixed length.
U.S. Patent 4,117,893 shows an agricultural
tool bar with individual wheel assemblies that are
adjusted through the extension and retraction of
hydraulic cylinders for depth control. The cylinders
are also mounted directly between the frame and the
wheel assemblies and have the same problems as those
shown in U.S. Patent 4,194,573.
U.S. Patent 4,106,568 shows a chisel plow
with a rock shaft depth control of the conventional
type. The devlce of the present invention is
designed specifically to correct the torsion loading
present in the axle tubes shown in Patent 4,106,568.
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Threaded adjustments are known for adjusting
depth controls. For example, in ~.S. Patent 2,655,351
there is a lift cylinder supported on an overhead
frame and which acts directly to pivot a support
memher for the wheels and has a threaded piStOIl rod
for adjustment purposes. U.S. Patent ~,117,893 also
shows a cylinder mounted on an overhead frame and
operable for raising and lowering support wheels.
Threaded stops are also known. For example,
~S. Paten-t 3,700,0~3 shows a threaded stop for
stopping movement of the piston rod in a desired
location.
Typical additional patents which illustrate
the state of the art and which were uncovered in the
course of a preliminary search include U.S. Patents:
1,844,124; 3,090,446; 3,648,780; 3,172,218; and
~,077,477.
SUMMARY OF THE INV~NTION
The present invention relates to a lift
mechanism using a double acting hydraulic cylinder in
the lift mechanism which acts directly on a pivoting
axle leg that supports the wheels of an implement.
The axle leg is fixed to a pivoting axle tube which is
pivotally supported on the implement frame. The
cylinder is connected ~o a mast that is rotatably or
pivotally mounted on the axle tube. An adjustable
reaction link is used for reacting load from the mast
(as it tends to rotate) back to the implement frame.
All supporting components are stressed in either
tension or compression (except for small torsion loads
caused by frictional forces in the rotational
mountinys of the axle tube) thereby simplifying the
construction of the lift frameworlc itself and
additionally permitting reduction in the size and
weight of the axle tube.
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The forces are resolved into the tension and
compression component6 by use of the described three
bar linlcage, which eliminates substantial torsion
loadiny in any parts caused by t~e load on the wheels
supporting -the implement.
A simple length acljustment link is used to
permit compensation for wear giving a strong,
economical and very reliable lift mechanism.
BRIEF DESCRIPTION OF T~IE DRAWINGS
Figure 1 is a fragmentary side elevational
view of a typical tool bar implement frame having
support wheels operated by an integral lift cylinder
mechanism made according to the present invention; and
Figure 2 is a top plan view of the device of
Figure 1.
ESCRIPTION OF T~IE PREF~RRED EMBODIMENT
An implement frame indicated generally at 10
is shown only schematically in the present drawings,
because it can be any desired type o~ Erame such as
those discussed in connection with the prior ar-t
identified above, or tool bar frames used for field
cultivators and chisel plows and air seeders made by
Wil-Rich, Inc., of Wahpeton, North Dakota, the
assignee of the present application. The frame 10
includes fore and aft extending rame members 12, 12
which are spaced transversely apart and fixed in place
with transverse frame members 130 Suitable cross
braces 14 can be used on the frame 10, if desired~
Cross members 15 are used adjacent the wheel mounting
regions for additional strength.
The lateral or transverse frame members 13
are used for mounting suitable earth working tools or
other devices (no-t shown) such as field cultivator
shank assemblies or chisel plow shank assemblies.
The height of the frame 13 relative to the
ground level is controllable with the device of the
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present invention by controlling the relative
positions of a plurality of walking beam assemblies
20, one of which is shown in the drawings. The
walking beam assembly 20 carries spinclles 22, 22 on
S which the wheels 21, 21 are mounted. The walking beam
assembly 20 in turn is pivotally mounted on a support
shaft 23 that is mounted at the end of an axle leg
24. The upper end of the axle leg 24 is welded to an
axle tube 25.
The axle tube 25 in turn is rotatably
mounted in a pair of bearing supports 26, 26 which in
turn are supported on axle tube supports 27, 27. Each
of the axle tubes supports 27 is supported from a
separate one of the fore and aEt frame members 12, and
the axle tubQ 25 is prevented Erom sliding axially
relative to the bearing supports 26 by suitable stop
members 28 which are welded to the tube but yet will
permit the tube to ~otate during adjustment of the
axle leg. The vertical position of the wheels 21, 21
relative to the frame is adjusted by controlling the
pivotiny o~ the axle tube.
In many previous devices, the adjustment of
height of the frame relative to the wheels has been
accomplished by having the axle tube 25 act as a
torsion shaEt which is operated by a cylinder that
is offset from the center line of the axle leg 24. In
previous lift arrangements substantial torsion loads
were introduced into tne axle tube, requiring heavier
tubes with greater wall thicknesses and larger
diameters than needed with the present lift.
The device of the present invention
eliminates torsion loads in the axle tube by providing
a three bar linkage illustrated generally at 30 to
support the loads on the axle leg ~rom the wheels 21
and react the loads back to the frame.
The three bar linkage includes a rnast
assembly 31 that comprises a pair of spaced members 32
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which are rotatably mounted on the axle tube 25
through the use of a pair of ~ast bearing caps 33~ one
of which is suitably attached to each of the members
32. Mast assembly 31 further includes a cylinder
support ear 34 that is mounted between the members 32,
32 at the upper ends thereoE~ Ear 34 is provided witn
an aperture that receives a mounting pin 35 for
pivotally mounting the base end of a double ac-ting
hydraulic cylinder assembly 37 to support ear 34. The
cylinder assembly 37 is operated through a suitable
valve 38 to extend and retract a cylinder rod 41. Xod
41 has a clevis or rod end 42 pivotally mounted by a
pin 43 to an ear 44 that is fixed to the axle leg 24.
An adjustable mechanical stop member 45 i5
mounted on the cylinder rod 41 so that the retracted
position of the rod can be mechanically dekermined.
The stop 45 will engaye the end of the cylinder to
provide a precise mechanical location for the lowest
position of the frame. The stop 45 is adjustable to
permit a fixed position to be achieved when retracting
the cylinder assembly 37.
The force or load from the weight supported
by wheels 21 that is reacted by the lift cylinder
assembly 37 to the mast assembly is transmitted back
to the frame 10 through a force link 50. The mast, as
previousl~ explained, is free ~o rotate on the tube
25.
The force link 50 comprises a tube tnat is
pivotally mounted at one end as at 51 between the mast
members 32, 32 of the mast assembly. A threaded
adjus-tment rod 52 is threaded through a nut 53 which
is welded to the end of the tube. The rod 52 can be
threaded to change the length of the force link as
desired. The lower end of the force link, comprising
the threaded rod 52, is mounted through an anchor
assembly indicated generally at 55 that includes a
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cross member 56 that has an opening through which the
threaded rod 52 is passed. Loclc nuts 57 are used for
clamping the lower end oE the rod 52 and thus the
lower end oE the force linlc securely to the anchor
assembly. In addition to the cross member 5~, the
anchor assembly has Eore and aft extending mernbers 58
that are attached to lateral frame members 13 and 15
with U bolts, as shown in Figure 1, so -that the force
link is securely anchored baclc to the implement frame.
As mentioned, the Eorce exerted on the axle
leg 24 by the lift cylinder 37 is carried baclc to the
mast assembly 31 which is free -to rotate on the axle
tube 25, and the load is reacted throuyh the force
link 50 back to the frame. ~'his puts the cylinder
assembly 37 in compression and the force link 50 in
compression while the mast assembly carries some
tension. The axle tube 25 is not subjected to torsion
loads during the raising and lowering operations.
Additionally, the length of force link 50 can be
adjusted to compensate for wear and the stop 45 can be
utilized for letting the lift cylinder return to a set
position when it is retracted to lower the frame
relative to the ground.
Thus, a simple framework is utilized by
having a mast that pivots relative to the movable or
pivoting axle support, ~hich is direc-tly centered on
the axle leg. The linkage mechanism carrying the
implement load forces are subjected to tension and
compression load rather than torsion loads.
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